Short answer
A test of whether people with disabilities can use your website, measured against the Web Content Accessibility Guidelines (WCAG). A proper one combines automated scans with checks only a person can do, and ends with a list of barriers and how to fix them.What gets tested
WCAG is built on four principles, and an audit checks each:
- Perceivable: can everyone take in the content? Image descriptions, color contrast, captions on video.
- Operable: can everyone use it? Keyboard access, visible focus, enough time to complete tasks.
- Understandable: labels on form fields, clear error messages, predictable behavior.
- Robust: is the code clean enough that screen readers and other assistive technology can interpret it?
Automated and manual, not one or the other
Scanners are fast and consistent, and catch the mechanical problems. But the W3C says “tools cannot check all accessibility aspects automatically. Human judgement is required”, and warns that “sometimes evaluation tools can produce false or misleading results” (W3C). Whether an image description is actually useful, or whether a form makes sense to someone using a screen reader, takes a person to judge.
What you should get
- A list of barriers, each tied to the WCAG criterion it fails.
- Where each one is on your site, so it can be found and fixed.
- An order to fix them in, starting with what blocks people most.
- The date and scope of the test, so you know what it covered.
Why businesses do it
Partly because people who can't use your site can't become customers. Partly because the US Justice Department says the ADA covers what businesses open to the public offer on the web (US Department of Justice). More on what that means for a small business.
How we do it
We run real scans with axe-core, the open-source engine many accessibility tools are built on, check the results by hand, and report only what we measured. We hold our own site to the same standard and publish the results with their date.